1. Field of the Invention
Embodiments of the present invention generally relate to methods and apparatus for polishing a substrate, such as a semiconductor substrate. More specifically, embodiments of the present invention relate to methods for conditioning a polishing surface in a chemical mechanical polishing (CMP) system.
2. Background
During the manufacture of semiconductor devices, layers and structures are deposited and formed on a semiconductor substrate by various processes. Chemical mechanical polishing (CMP) is a widely used process by which a polishing pad in combination with a polishing solution removes excess material in a manner that planarizes the substrate or maintains flatness for receipt of a subsequent layer. Over time, the effectiveness of the polishing pad diminishes. In order to improve the effectiveness of the polishing pad the polishing pad may be periodically conditioned.
Pad conditioning generally involves scouring the polishing pad with an abrasive conditioner disk to remove any accumulated polishing by-products on the pad surface and/or to refresh the surface of the polishing pad. When new CMP consumables, such as polishing pads and conditioner disks are introduced into a polishing system, the properties and/or interaction with each other are not known. For example, conditioner disks vary from manufacturer to manufacturer and often times vary from disk to disk. As such, a new conditioner disk may under-condition the polishing pad, which results in lower removal rate, or over-condition the polishing pad, which results in decreasing the lifetime of the polishing pad. Similarly, polishing pad properties may vary from manufacturer to manufacturer and from polishing pad to polishing pad. For example, properties of the polishing pad, such as hardness, may affect the conditioning recipe causing the polishing pad to be over-conditioned or under-conditioned.
Thus, there is a need for an improved apparatus and method for conditioning a polishing pad and improve polishing pad conditioning based on the properties and interaction of consumables, such as the properties of polishing pads and properties of conditioner disks.